Method of forming flexible tubing



July 12, 1960 Filed Feb. 18, 1955 B; P. COLEMAN METHOD OF FORMING FLEXIBLE TUBING 2441 i i I l l 6 35 Q 5 Sheets-Sheet 1 IN VEN TOR.

38625711? Coleman BY I July 12, 1960 3 Sheets-Sheet 2 Filed Feb. 18, 1955 IN V EN TOR.

k A a Q F 6 w 6W w 6 6 1% w 6 6 v u 4 \M Z 7 7 Wfij 6 6 5g 66 L 6 g M 6 6 $6 July 12, 1960 B. P. COLEMAN 2,944,337

METHOD OF FORMING FLEXIBLE TUBING Filed Feb. 18, 1955 I s Sheets-Sheet s &

Ill T INVEN TOR. fieaZorl? @Zemam BY M M 1 W METHOD OF FORMING FLEXIBLE TUBING Bestor P. Coleman, Willow Springs, 111., assignor to Acme Steel Company, Chicago, Ill., a corporation of Illinois Filed Feb. 18, 1955, Ser. No. 489,027

10 Claims. (Cl. 29-417) This invention relates to improvements in flexible tubing and its purpose is to provide a novel method of severing flexible tubing to form sections of the required lengths and then fastening the cut ends.

Flexible tubing formed of galvanized steel strips Wound in helical fashion is now in use for a variety of purposes including uses as air ducts in heating systems and the like, and it is necessary to cut the tubing to form sections of various lengths. When the tubing is cut the steel strip of which it is formed tends to unwind due to the resilience of the metal so that the ends of the cut lengths are unsatisfactory for use. So far as is known, no suitable means for overcoming this difliculty has heretofore been devised.

The principal object of the present invention is to provide an improved method and means for severing the tube by cutting a convolution of the metal strip and stitching the cut ends of this convolution to adjacent portions of the tube. A further object is to provide a method according to which the flexible tubing is severed by cutting it transversely to a convolution of the helical winding and then uniting the cut ends to adjacent convolutions by stitching or other fastening means which is diagonally arranged so that it acts to resist the tendency of the cut end to uncoil itself due to its own resiliency. Another object is to provide a helically wound metal tube having its ends secured in a novel manner. Other objects relate to various features of the improved method and tubing which will appear more fully hereinafter.

The nature of the invention will be understood from the following specification taken with the accompanying drawings in which one example of the invention is illustrated. In the drawings,

Figure 1 shows a side elevation of a section'of flexible tubing formed according to the present invention with parts thereof cut away, illustrating the methodof cutting a convolution of the tubing and showing two wire stitches by which the end portions of the tubing on opposite sides or the out are united with adjacent convolutions;

Fig. 2 shows a side elevation of the ortions of tubing illustrated in Fig. 1 after they have been separated by relative rotation of the two sections;

Fig. 3 shows a perspective view of a portion of the tubing illustrated in Fig. 1 before it has been cut or stitched, illustrating one method of winding a flexible metal strip to form a helically wound tube;

Fig. 4 shows a side elevation of one form of machine which may be used in forming the tubing illustrated in Fig. 1 with the use of the forming die which is illustrated in Fig. 3;

Fig. 5 shows an enlarged side elevation of and partial vertical section through the stitching mechanism which is embodied in the machine shown in Fig. 4;

Fig. 6 shows a horizontal section taken on the line 6-6 of Fig. 5;

Fig. 7 shows a vertical section taken on the line 77 of Fig. 6;

Fig. 8 is a view similar to that of Fig. 5 showing the ice relative positions of the parts during the driving of the staples;

Fig. 9 shows an enlarged vertical section taken on the line 99 of Fig. 8; and

Fig. 10 shows an enlarged vertical section taken on the line 1010 of Fig. 8.

As illustrated in Figs. 1 and 2 of the drawings the flexible tubing 15 of the present invention is made up of a series of convolutions of a metal strip 16 which has a flattened S-shaped cross section. This metal strip is wound in helical fashion so that the outwardly projecting portion 16a at one edge of the strip interlocks with the underlying edge portion 16b at the other edge of the strip in an adjacent convolution of the winding. The strip 16 is formed preferably of galvanized steel having considerable resiliency so that the convolutions of the tube have a natural tendency to unwind in an outward direction, thus maintaining a tight connection between adjacent convolutions of the strip while permitting some relative endwise and angular movement of adjacent convolutions so that the tubing is flexible and may be caused to occupy a variety of positions as required by the use to which it is put.

The present invention involves a novel method of severing the tubing 15 into sections of the desired length, while at the same time fastening the ends of the sections at the place where the cutting occurs so that the unwinding of the convolutions at the ends of the sections is prevented. For this purpose, the tubing is cut at one place around its periphery in order to sever one of the convolutions and this is preferably done by punching a portion of the metal out of the convolution along a diagonal line to form an elongated hole 17. This hole extends at an angle to the longitudinal axis of the tube 15 and is of such length that it extends beyond the convolution 18 which is severed and projects into adjacent convolu tions 18a and 18b. Before punching the hole 17 to cut the convolution 18, or simultaneously with the operation of punching the hole 17, the convolution 18 is stitched to the adjacent convolutions 18b and by elongated wire stitches 19 which are located on opposite sides of the place where the hole 17 is to be formed and parallel to the longitudinal axis of this hole. Thus, when the hole 17 is punched through the convolution 18 and partially through the adjacent convlutions 18a and 18b, the ends of the convolutions 18 on opposite sides of the hole 17 are secured to the adjacent convolutions 18a and 1811 by the stitches 19. When the stitching and punching operations have been completed, the two sections 15d and 15b of the tubing may be rotated with respect each other about their longitudinal axes, thus causing the convolutions on opposite sides of the hole 17 to be unscrewed from each other so that the interlocking connection between the sections 15a and 15b is broken and these two sections are then separated as shown in Fig. 2. Although it is preferable to form the stitches 19' before or simultaneously with the operation of punching the hole 17, the hole 17 may be punched first, provided the two sections 15a and 15b are not separated prior to the formation of the stitches, because each convolution interlocks with the edge of an adjacent convolution and this interlocking connection holds them together.

When the convolution 18 to be severed is stitched to the adjoining convolutions, the staples 19 are clinched on the inside of the tubing 15 against a suitable anvil and a supporting anvil may be located on the inside of the tube to permit a portion of the metal to be punched out to form the hole 17 simultaneously with the act of forming the stitches 19 or immediately following the stitching operation.

The cutting of the convolution 18 of the tubing and the driving of the staples 19 may be performed manually As the downward movement ofthe former, 40 continue s, the ends of the sections30a of the. stitchingwire which project. on opposite sideszof-the anvil 47d are bent downwardly to form. the legslof the staples; These downwardly bent portions of the stapling wire then travel in grooves Me which are formed-in. the sides of the members 41a within the slotsin which the. driving mexnbers 40-are adapted to travel. the formation of the staples is completed, the former 40 will. have reached a stage of its downward movement where the portions 47a of. the members 47 ride inwardly over the cams 53 under the influence of the spring actuated plunge rs 50 so that they are then retracted to positions: such shown in Fig, 8; The drivingofthe staples through the tubing 15is then effected by the downward movement of the driving members 44 and, during: thisv operation, the staples are-supported on their lateral-sides by means of the supporting shoes 60 which are carried by arms 60:: supportedon the bars 61' which'are pivoted at 62 onthe casing 38. The supporting shoes 60 are thus adapted to swing. about the pivot 62to and from staple supporting positions and this movement is" effected by a mech= anism -including links 63 pivotally connected at, to the upper ends of the arms 60a and pivotally connected at 6 5 to *apiston rod' ex-tending downwardly from cylinders '67 in which pistons. are operated by spring pressure, compressed air, or the like; in order toflcause the staple supporting. members 60-to occupy their inner mostpositions wherein theyare adapted toextendb'etween the legs of the staples and to'su-pportthese legs as the staplesare driven by the members 44,- As the driving of the staple nears completion, the outwardly and upwardly inclinedfaces 60b on the shoes-60--are engaged by the lower outer edges of the'former 40, and these shoes'are thereby cammedoutof position until they occupy the retracted positions shown in- Fig. 8. As the'staples are: driven the" legs thereof. are extended through. the convolutionsof the tubingIS' sothat each staple 1 9' occupies the position shown in Fig, 9 with the top wall of the staple resting against: the outer face of the convolutionsls of the" tubingrand with the :legs 19a: of the staple extending through the convolutions and clinched on the inner side of thetubing- This clinching is effected by the die'23 which is provided on its upperface with curved guide surfaces 232i adapted to engage the ends ofthe legs 19a of the staple and to curve them inwardly-as the staple is approaching the endofthe driving operation, I

'At the same time that the stapling of the convolutions of the tubingtis performedby thedownward movement of: the staple drivers 44, the punch. 43 is moved downwardly'and it is actuated to form the hole 17 inthetubing t th same t me, or immediately af e t mpl ti off. he. t rm ion. of the. stitches was wn F -o When the hole 17 and the stitches 19 have been completed in the manner just described the staple former 4t and the other parts are retracted inreadiness for a new operation and the section 15b of the tubing which has been severed is removed by relative rotation with re spect to that portion of the tubing which is still in engagement with the die plate 35. The formation of an additional length of tubing by. pushing the metal strip 16 in the direction of the arrow 37, through the use of suit-.

7 able power driven feeding mechanism, is then continued until a new length of tubing of the desired extent has been formed.

The machine described above for carrying out the operation of cutting the flexible metal tubing and fastening the ends thereof does not in itself constitute a part of the present invention but will be made the subject matter of a copending application.

It'will be observed that the present invention has the.

advantage of providing means for severing the helically wound tube by cutting a single convolution thereof and for uniting the ends of the tubing on opposite sides of 6 l the cut with adjacent convolutions of the tubing so that the tightly wound condition of the tubing is maintained even at those points which are in proximity to the place where the cut has been made. In. this connection it is importantto locate the stitches 19 so t hat they extendin diagonal directions with respect to the longitudinal axis of the tubing and do not permit any substantial pivotal movement which might allow an outward deflection of the extremities of the convolutions proximity to the place where the cut has been made. To accomplish these results it is desirable that the. punch by which the hole 17 is formed and the staples 19 be located in parallel planes which are diagonal to a plane containing the longitudinal axis of the tubing.

Although on form of the improved tubing and one method of forming thistubing have beenillustrated and described; it wili be understood that the invention may take various: forms and be practiced in various ways without: departing from the scope of the appended claims;

I claim: N r V p I 1 'l'he method of severingmetal tubing formed by a helical winding .ofa metal strip so as to provide separate lengths of the tubing which comprises the steps of cutting a convolution of the winding transversely, and securing the respective cnt ends of the said convolution to nextadjacent unsevered: parts of; thetubeby stitches extend-- ing. parallel to theplane' of the cut.

The method-of severing. metal tubing formed by a helical winding of a resilient metal strip so as to provide separate lengths of the tubing which comprises the steps of cutting a convolution transversely and diagonally to the longitudinal axis of the-tube and securing the respec: tive severed ends; of saidconvolut-ion to next adjacent unsevered convolutions by elongated stitches extending:

parallel; to the plane ofi thecut-i' n 3. '1. -he" method;o severing metal tubing termed by a helical windirig of a resilient/metal strip so as to provide separate lengths of the tubing which comprises the steps of. punching an elongated hole through the tube to sever one convolution "thereofand securing the-respective severed-ends oisaid convolution to next adjacent unsevered convolutions by elongated wire stitchesextending paralle l'to said hole on opposite sides thereof; v

r Tha -method of severing metal tubing formed by a helical winding of a resilient-metal strip so as to provideseparatelengths ofth'c tubing: which comprises the steps of punching an elongated hole through the'tube at an angle to the: longitudinal axis ot 'the tube to sever one convolution thcreof and securing the respective severed: ends of saicb convolutionto nextadjacent unsevered convolutions on opposite" sidesof-said hole by stitches extending parallel to said'hole;

5. '1fhe method or form-ing separate predetcrmined lengths oi heIica'L tubing comprisingt the steps; of forming a first predetermined length of said tubing and a connected portion only of a second length of said tubing by helically and progressively winding a continuous metal strip, separating said first predetermined length of tubing from said portion of said second predetermined length by severing transversely one of the convolutions of said metal strip at the junction of said lengths, stitching one severed end of the severed convolution to the next adjacent convolution of the metal strip in said first predetermined length, stitching the other severed end of said severed convolution to the next adjacent convolution in said portion of said second predetermined length, and then forming the remainder of, said second predetermined length of tubing by resuming said helical and progressive winding of said strip.

6. The method of forming separate predetermined lengths of helical tubing, comprising the steps of forming a first predetermined length of said tubing and a connected portion only of a second length of said tubing by helically and progressively winding a continuous metal strip, separating said first predetermined length of tubing from said portion of said second predetermined length by cutting transversely one of the convolutions of said metal strip at the junction of said lengths, stitching one of the cut ends of the severed convolution to the next adjacent convolution of the metal strip in said first predetermined length by a stitch extending substantially parallel to the plane of the cut, stitching the other cut end of said severed convolution to the next adjacent convolution in said portion of said second predetermined length by another stitch extending substantially parallel to the plane of the cut, and then forming the remainder of said second predetermined length of tubing by resuming said helical and progressive winding of said strip.

7. The method of forming separate predetermined lengths of helical tubing, comprising the steps of forming a first predetermined length of said tubing and a connected portion only of a second length of said tubing by helically and progressively Winding a continuous metal strip, separating said first predetermined length of tubing from said portion of said second predetermined length by transversely cutting one of the convolutions of said metal. strip at the junction of said lengths along a plane disposed diagonally with respect to the axis of the tubing, stitching one of the cut ends of the severed convolution to the next adjacent convolution of the metal strip in said first predetermined length by a stitch extending substantially parallel to the plane of the cut, stitching the other cut end of said severed convolution to the next adjacent convolution in said portion of said second predetermined length by another stitch extending substantially parallel to the plane of the cut, and then forming the remainder of said second predetermined length of tubing by resuming said helical and progressive Winding of said strip.

8. The method of forming separate predetermined lengths of helical tubing, comprising the steps of forming a first predetermined length of said tubing and a connected portion only of a second length of said tubing by helically and progressively Winding a continuous metal strip, separating said first predetermined length of tubing from said portion of said second predetermined length by punching an elongated hole through the tubing at the junction of said lengths to sever one convolution of said strip at said junction, stitching one severed end of the severed convolution to the next adjacent convolution of the metal strip in said first predetermined length, stitching the other severed end of said severed convolution to the next adjacent convolution in said portion of said second predetermined length, and then forming the remainder of said second predetermined length of tubing by resuming said helical and progressive winding of said strip.

9. The method of forming separate predetermined lengths of helical tubing, comprising the steps of forming a first predetermined length of said tubing and a connected portion only of a second length of said tubingby helically and progressively winding a continuous metal strip, separating said first predetermined length of tubing from said portion of said second predetermined length by punching an elongated hole through the tubing at the junction of said lengths to sever one convolution of said strip at said junction, securing one severed end of the severed convolution to the next adjacent convolution of metal strip in said first predetermined length by an elongated wire stitch extending substantially parallel to said hole and along one side thereof, securing the other severed end of the severed convolution to the next adjacent convolution in said portion of said second predetermined length by another elongated Wire stitch extending substantially parallel to said hole and along the other side thereof, and then forming the reminder of said second predetermined length of tubing by resuming said helical and progressive winding of said strip.

10. The method of forming separate predetermined lengths of resilient metal helical tubing, comprising the steps of forming a first predetermined length of said tubing and a portion only of a second predetermined length connected to said first length by progressively Winding in helical form a continuous strip of resilient metal, separating said first predetermined length of tubing from said portion of said second predetermined length by punching an elongated hole through the tubing at an angle to the longitudinal axis of the tubing and at the junction of said lengths to sever one of the convolutions of said strip at said junction, securing one severed end of the severed convolution to the next adjacent convolution of the metal strip in said first predetermined length by an elongated Wire stitch extending substantially parallel to said hole and along one side thereof, securing the other severed end'of the severed convolution to the next adjacent convolution in said portion of said second predetermined length by another elongated wire stitch extending substantially parallel to said hole and along the other side thereof, and then forming the remainder of said second predetermined length of tubing by resuming said helical and progressive winding of said strip.

References Cited in the file of this patent UNITED STATES PATENTS 119,621 Leas et al Oct. 3, 1871 1,057,763 Mueller et a1. Apr. 1, 1913 1,348,793 Fulton Aug. 3, 1920 1,492,075 Fulton et a1. Apr. 29, 1924 1,789,191 Richard Ian. 13, 1931 2,095,599 Gleason Oct. 12, 1937 2,276,640 Ansel Mar. 17, 1942 2,513,431 Sell July 4, 1950 2,697,274 Merrill Dec. 21, 1954 

